static error

[Allan Bruce]

Hi there,
I get a linker error with the following, can somebody tell me how to remedy
it? the error is:
--------------------Configuration: WinGalaga - Win32
Release--------------------
Linking...
Weapon.obj : error LNK2001: unresolved external symbol "protected: static
int Weapon::mCurrLi ght" (?mCurrLight@We apon@@1HA)
WeaponManager.o bj : error LNK2001: unresolved external symbol "protected:
static int Weapon::mCurrLi ght" (?mCurrLight@We apon@@1HA)
Release/WinGalaga.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.

WinGalaga.exe - 3 error(s), 0 warning(s)


I am trying to initialise the lights from the WeaponManager by:
Weapon::InitLig hts();


Here is the header of the file where the problem exists


class Weapon : public GameEntity
{
friend class WeaponManager;

public:
Weapon(void);
virtual ~Weapon(void);

virtual void Draw(void);
void DrawLight(void) ;
static void InitLights(void ){mCurrLight = GL_LIGHT1;}

...

protected:
...
// light stuff
static int mCurrLight;
};


Thanks
Allan

[Karl Heinz Buchegger]

Re: static error



Allan Bruce wrote:[color=blue]
>
> Here is the header of the file where the problem exists
>
> class Weapon : public GameEntity
> {
> friend class WeaponManager;
>
> public:
> Weapon(void);
> virtual ~Weapon(void);
>
> virtual void Draw(void);
> void DrawLight(void) ;
> static void InitLights(void ){mCurrLight = GL_LIGHT1;}
>
> ...
>
> protected:
> ...
> // light stuff
> static int mCurrLight;
> };[/color]

this *declares* a variable mCurrLight. But it does not *define* it.
In other words: the above says: Somewhere there is a variable
called Weapon::mCurrLi ght and it has type int.
But where is that variable?
You have to define it somewhere, eg. in Weapon.cpp

#include "Weapon.h"

int Weapon::mCurrLi ght; // Here it is!!!

Weapon::Weapon( )
{
...


Your textbook should have a section on statis class members. Doesn't it?

--
Karl Heinz Buchegger
kbuchegg@gascad .at

[Allan Bruce]

Re: static error


"Karl Heinz Buchegger" <kbuchegg@gasca d.at> wrote in message
news:3FAB73CD.3 5A09455@gascad. at...[color=blue]
>
>
> Allan Bruce wrote:[color=green]
> >
> > Here is the header of the file where the problem exists
> >
> > class Weapon : public GameEntity
> > {
> > friend class WeaponManager;
> >
> > public:
> > Weapon(void);
> > virtual ~Weapon(void);
> >
> > virtual void Draw(void);
> > void DrawLight(void) ;
> > static void InitLights(void ){mCurrLight = GL_LIGHT1;}
> >
> > ...
> >
> > protected:
> > ...
> > // light stuff
> > static int mCurrLight;
> > };[/color]
>
> this *declares* a variable mCurrLight. But it does not *define* it.
> In other words: the above says: Somewhere there is a variable
> called Weapon::mCurrLi ght and it has type int.
> But where is that variable?
> You have to define it somewhere, eg. in Weapon.cpp
>
> #include "Weapon.h"
>
> int Weapon::mCurrLi ght; // Here it is!!!
>
> Weapon::Weapon( )
> {
> ...
>
>
> Your textbook should have a section on statis class members. Doesn't it?
>[/color]

Thanks, thats it working now.

My book does have a section on static members, but it is not explained very
well. I understand why you need the inclusion of Weapon::mCurrLi ght;

Thanks again
Allan

[Frank Schmitt]

Re: static error

"Allan Bruce" <allanmb@TAKEAW AYf2s.com> writes:
[color=blue]
> Hi there,
> I get a linker error with the following, can somebody tell me how to remedy
> it? the error is:
> --------------------Configuration: WinGalaga - Win32
> Release--------------------
> Linking...
> Weapon.obj : error LNK2001: unresolved external symbol "protected: static
> int Weapon::mCurrLi ght" (?mCurrLight@We apon@@1HA)
> WeaponManager.o bj : error LNK2001: unresolved external symbol "protected:
> static int Weapon::mCurrLi ght" (?mCurrLight@We apon@@1HA)
> Release/WinGalaga.exe : fatal error LNK1120: 1 unresolved externals
> Error executing link.exe.
>
> WinGalaga.exe - 3 error(s), 0 warning(s)
>
>
> I am trying to initialise the lights from the WeaponManager by:
> Weapon::InitLig hts();
>
>
> Here is the header of the file where the problem exists
>
>
> class Weapon : public GameEntity
> {
> friend class WeaponManager;
>
> public:
> Weapon(void);
> virtual ~Weapon(void);
>
> virtual void Draw(void);
> void DrawLight(void) ;
> static void InitLights(void ){mCurrLight = GL_LIGHT1;}
>
> ...
>
> protected:
> ...
> // light stuff
> static int mCurrLight;
> };[/color]

You have *declared* Weapon::mCurrLi ght, but you haven't *defined* it -
just add

int Weapon::mCurrLi ght;

to Weapon.cpp

HTH & kind regards
frank

--
Frank Schmitt
4SC AG phone: +49 89 700763-0
e-mail: frankNO DOT SPAMschmitt AT 4sc DOT com